Swinging propeller blade



E. P. WARNKEN SWINGING PROPELLER BLADE July 31, 1962 2 Sheets-Sheet 1 Filed May 28, 1957 Fig.4.

INVENTOR. Elmer P. Warnken ATTORNEYS y 1962 E. P. WARNKEN 3,047,726

' SWINGING PROPELLER BLADE Filed May 28, 195"! 2 Sheets-Sheet 2 INVENTOR. Elmer P. Warnken ATLORNEYS United States Patent 3,047,726 SWINGING PROPELLER BLADE Elmer P. Warnken, Cincinnati, Ohio, assignor, by mesne assignments, to Studebaker-Packard Corporation, South Bend, Ind., a corporation of Michigan Filed May 28, 1957, Ser. No. 662,232 2 Claims. (Cl. 290-55) This invention relates to the construction of propellers. When a propeller passes from one fluid to another, or from a stationary to a fast-moving fluid stream, very large forces may be encountered in the blades of the propeller which can cause failure of propeller blades. An

object of this invention is to provide a propeller having blades which are adapted to swing or pivot to minimize such sudden changes of force on the propeller blades.

An aerial torpedo of the type dropped by an'airplane into water may enter the water at a speed substantially In aircraft, it often is the practice to pi'ovide an air driven auxiliary generator which can beused to'generate electric power'in the event of failure of conventional sources of electric power. Such an auxiliary generator is normally housed inside the aircraft and may be dropped or pushed into an air stream when required. Upon entry of the auxiliary generator into the air stream, violent forces are encountered by the blades of the propeller thereof. A further object of this invention is to provide a propeller for driving an auxiliary generator, or the like, having blades which pivot freely to relieve shock incident to entry into an air stream and in which centrifugal force caused by rapid rotation holds the blades in proper position during operation of the generator.

The above and other objects and features of the invention will be apparent to those skilled in the art to which this invention pertains, from the following detailed description, and the drawings, in which:

FIGURE 1 is a view in side elevation of a torpedo having propeller blades constructed in accordance with an embodiment of this invention;

FIG. 2 is an enlarged fragmentary view in lengthwise section, partly broken away, showing the tail portion of the torpedo illustrated in FIG. 1;

FIG. 3 is a fragmentary view in transverse section, showing one blade of the propeller and the mounting thereof;

FIG. 4 is a view taken in the direction of the arrows 44 in FIG. 3;

FIG. 5 is a perspective view of an air driven generator having propeller blades constructed in accordance with another embodiment of this invention;

FIG. 6 is a fragmentary view in transverse section of the fuselage of an aircraft equipped with the generator illustrated in FIG. 4, the generator being shown in retracted position in dotted lines, and in operative position in full lines; and

FIG. 7 is an enlarged view of one of the blades of the propeller of the device illustrated in FIGS. 4 and 5, alternate positions thereof being shown in dotted lines.

In the following detailed description, and the drawings, like reference characters indicate like parts.

In FIG. 1 is shown an aerial torpedo 10 of the type which is dropped from an aircraft into a body of water and travels in the water. At the tail of the torpedo is mounted a shroud 12.

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As shown in FIG. 2, the shroud 12 is supported by a plurality of forward and rear struts, indicated at 13 and 14, respectively. Only one forward strut and one rear strut or stator vane are shown, but it is to be understood that a sufficient number of struts is provided to properly support the shroud. In a preferred form of torpedo, six equally spaced forward struts and twelve equally spaced stator vanes may be provided. The struts 13 and stator vanes 14 are mounted on sections at 16 and 17, respectively, of the torpedo body. Between the body sections 16 and 17 is mounted a propeller supporting ring or hub 19, only' a portion of which is shown. The hub 19 is rotated by mechanism (not shown) inside the body of the torpedo. The structure described to this point may be of the type common in aerial torpedos. Appropriate steering mechanism (not shown) may be provided for directing the torpedo as it advances through the water.

The torpedo is driven through the water by propeller blades 21 (only one of which is shown). The propeller blades are mounted on the propeller supporting ring 19. The ring 19 is provided with a plurality of bosses 22 (only one of which is shown). Each boss supports one of the propeller blades. A suitable number of bosses and propeller blades may be provided. In a preferred torpedo, twelve bosses and twelve equally spaced propeller blades may be provided. The blades may be made of any appropriate rigid material, such as a metal or other suitable material.

As shown in FIGS. 2 and 4, the boss 22 carries upstanding lugs 23 and 24. The inner end of the blade is slotted, as indicated at 26 and 27, to receive the lugs 23 and 24. A pivot pin 28 pivotally connects the propeller blade with the. boss 22. As indicated in FIGS. 2 and 4, the inner end of the propeller blade is enlarged and has a circularly cylindrical surface 29. The enlarged inner end of the propeller blade is provided with a bore 30 which extends substantially parallel with the inner end of the blade. The lugs 23 and 24 are provided with bores which are aligned with the bore at the inner end of the propeller blade, and the pivot pin 28 is received in the aforementioned aligned bores to pivotally support the propeller blade for swinging between the position shown in full lines in FIGS. 1 and 3 and the position shown in dotted lines. When the blade is in the position shown in full lines, a lug 33, which is integral with the blade between slots 26 and 27, engages a flat face 34 on boss 22 to limit swinging of the blade in a counter-clockwise direction, as shown in FIG. 3. As shown in FIG. 3, the outer face of the boss 22 has a concave portion 36 which has substantially the same curvature as the inner end of the blade.

Operation of the torpedo will be apparent from the foregoing detailed description. When the torpedo 10 is dropped from an aircraft, the torpedo may enter the Water at a speed substantially greater than that at which the torpedo is propelled through the water. As the propeller blades hit the water, the blades may swing back, as indicated in dotted lines in FIG. 2, so that the impact of the water on the blades is minimized. Then, as the hub 19 and the blades rotate through the water and the speed of the torpedo is reduced to that at which the torpedo is normally driven through the water, the blades swing up to the driving position shown in FIGS. 2 and 3 in full lines. When the blade 21 is in this position, the lug 33 thereof engages the face 34 of the boss 22 to limit swinging of the blade so that the blade is held in proper position for driving the torpedo.

In FIGS. 5-7 inclusive, is shown an auxiliary generator 41, provided with blades 42 and 43 constructed in accordance with another embodiment of this invention. The generator includes a body portion 44 inside which appropriate electrical generating apparatus (not shown) is housed. A hub 46 is rotatably mounted on the body in appropriate bearings (not shown). The hub 46 is provided with radial bores 48 (only one of which is shown, see FIG. 7) in which blade-carrying shafts 49 are housed. Each shaft 49 has a circular head 51 which is mounted in a oounterbore 52 in the ring. As shown in FIG. 5, the head 51 carries outwardly extending lugs 53 and 54 which fit into slots in the inner end of one of the blades. As shown in FIG. 7, a pivot pin 56 extends through a bore in the inner end of the blade and through bores in the lugs to pivotally support the blade so that the blade can swing from the position shown in dotted lines at 42A through the position shown in full lines to that indicated in dotted lines at 42B.

The body of the generator is mounted on an angleshaped bracket 61 (FIG. 6). The bracket 61, in turn, is pivotally mounted inside the fuselage 62 of an aircraft. An actuator rod 63 is pivotally attached to the rod 61 adjacent a bend 64 thereof. The actuator rod may be advanced by appropriate mechanism (not shown) from the position shown in dotted lines to that shown in full lines to move the generator from the dotted line position in which the generator is housed inside the fuselage, to the full line position in which the generator is in the air stream adjacent the fuselage. The generator passes through an opening '66 in the side of the fuselage. A door 67 normally closes the opening. The door 67 swings open as the generator passes through the opening. A spring (not shown) on the hinge 69 of the door holds the door in open position.

When the generator is housed inside the fuselage, the blades are folded forwardly as indicated in dotted lines in FIG. 6. Then when the generator is pushed into the air stream, the blades swing back as they start to rotate the hub 56 and shafts 49. The generating apparatus (not shown) inside of the generator is driven by the hub 46 and shafts 49. As the speed of rotation increases, the blades are urged outwardly by centrifugal force, and the blades are held in extended position by centrifugal force during operation of the generator.

The devices illustrated in the drawings and described above, are subject to structural modification without depanting from the spirit and scope of the appended claims.

Having described my invention, what I claim as new, and desire to secure by Letters Patent, is:

1. In combination with an aircraft, a propeller driven generator which comprises a body, means for mounting the body for movement into and out of the aircraft a hub rotatably mounted on said body, a plurality of circumferentially spaced hinges mounted on said hub, and a propeller blade pivotally mounted on each of said hinges, the axis of the hinge of each blade extending chord-wise at the hub end of the blade and being skewed with relation to the hub, the blade swinging freely on the hinge on opposite sides of an outstanding extended position, the propeller blades being adapted to swing when the generator enters an air stream adjacent the aircraft, centrifugal force holding the blades in extended position when the blades are driven by the air stream.

2. In combination with an aircraft, a propeller driven generator which comprises a body, a hub rotatably mounted on said body, a plurality of circumferentially spaced hinges mounted on said hub, a propeller blade pivotally mounted on each of said hinges, the axis of the hinge of each blade extending chord-wise at the hub end of the blade and being skewed with relation to the hub, the blade swinging freely on the hinge on opposite sides of an outstanding extended position and means inside the aircraft for mounting the generator for movement between a housed position inside the aircraft and an operative position in the air stream adjacent the aircraft, the propeller blades being adapted to swing when the generator enters the air stream, centrifugal force holding the blades in extended position when the blades are driven by the air stream.

References Cited in the file of this patent 

